Both the physical and chemical properites of a substance can change when a substance undergoes a chemical reaction. when a log is burned, a chemical reaction occurs. the log is transformed into ash, water vapor, and carbon dioxide. the log is flammable, or able to be burned, in its original form. once the log is burned, however, the ashes that are produced are no longer flammable. the volume of the log also changes when it changes into ash and gas. volume is a property. flammability is a property. a. chemical; physical b. physical; physical c. physical; chemical urgent time limit 84pts